A Montana newlywed may be facing life in prison after being charged this week for her husband's murder after authorities say she admitted pushing him off a cliff at a national park just over a week after their wedding.

Jordan Linn Graham, 22, told FBI agents that she and her husband of eight days, 25-year-old Cody Lee Johnson, were arguing on July 7 while walking in Glacier National Park near their home in Kalispell, Mont. when he grabbed her arm, according to an affidavit filed at the federal district court of Montana.

"She could have just walked away, but due to her anger, she pushed Johnson with both hands in the back and as a result, he fell face first off the cliff," the affidavit states she told investigators.

Charging documents in the case reveal that Graham told a friend that she was having second thoughts about the marriage, and that she said that she wanted to talk about her issues with Johnson the night he died.

Graham also sent a message to her friend saying, ""But dead serious. If you don't hear from me at all again tonight, something happened," according to the affidavit.

Johnson was reported missing on Monday, July 8 after he failed to show up at work.

When interviewed by authorities on July 9, Graham said that she saw "a dark colored car pulling out of the driveway" after receiving a text from her husband saying he was heading out with a friend from out of town, according to the affidavit.

It was Graham who reported the discovery of Johnson's body to a park ranger on July 11, according to the affidavit. When the park ranger commented that it was unusual that she was the one to make the discovery, Graham said that "It was a place he wanted to see before he died."

"He would come up here with friends to drive fast when his friends were visiting from out of state," she said, according to the affidavit.

Police had to use a helicopter to retrieve Johnson's body from the steep cliffs below the park's Loop Trail. His body was recovered on July 12.

When interviewed by authorities on July 18, Graham admitted that she had lied about the death of her husband and provided false statements.

Graham, who is currently in custody, made an initial court appearance Monday at a federal court in Missoula, Mont., on a charge of second degree murder. It was not clear whether she entered a plea at that hearing and her attorney, public defender Michael Donahoe, declined comment to ABCNews.com.